Human liver s)alyltransferase will be solubilized with Triton X-100 (1.5%, V/v) and purified by affinity chromatography on either agarose-hexanolamine-cytidine diphosphate or agarose-ethanolamine-cytidine diphosphate. The postaffinity column enzyme will be further purified on sephadex G-150 by gel filtration. The purity of the enzyme will be assessed by polyacrylamide gel electrophoresis and, if homogeneous, kinetically characterized. Comparative characterization studies will also be done on sialyltransferases purified from metastatic tumor tissue of human liver and from cystic fibrosis livers. These studies may find reasons for the altered activity levels and/or properties of sialyltransferases which have been reported for these pathological tissues. In addition, the soluble sialoglycoconjugates of metastatic tumor sites of human liver will be characterized.